function Person(){
  this.name='icoder'
  this.age=18
  this.getAge=function(){
    return this.age
  }
}
const p = new Person
const a =p.getAge()


/**
 * 下面这样访问属性会更快点。
 */
function Person1(){
  this.age='icoder'
  this.age=18
}
const p1 = new Person
const b = p1.age